The present invention relates to an internal combustion engine controller applied to an internal combustion engine incorporating a turbocharger.
Japanese Laid-Open Patent Publication No. 2010-096049 discloses a controller for an internal combustion engine that reduces the response delay of a turbocharger by closing a waste gate valve when an acceleration request is detected. In this manner, it is known that in an internal combustion engine incorporating a turbocharger of an exhaust turbine type, the response of the turbocharger is delayed when acceleration starts. This delays the response of the acceleration.
When acceleration starts from a deceleration state, the rotation speed of a turbine wheel is low. Thus, the resistance is large when intake air passes through a compressor. That is, the pressure loss is large when the intake air passes through the compressor, and the flow of intake air drawn toward the downstream side of the compressor is inhibited. This may lower the supercharging pressure, which is the pressure of the intake air between the downstream side of the compressor and the upstream side of a throttle valve, when the air at the downstream side of the compressor is suctioned into the combustion chamber. The reduction in the supercharging pressure is one of the factors causing the response delay of acceleration.
In an internal combustion engine incorporating a turbocharger, it is desirable that the response delay of acceleration be reduced.